Yard and Garden: Fun Facts about Holiday Plants

December 18, 2018, 2:24 pm | Richard Jauron, Willy Klein

AMES, Iowa – If you are looking for a safe conversation topic for family holiday gatherings, look no further than the plants sure to be on display throughout the holidays. The history and bits of trivia about mistletoe, Thanksgiving and Christmas cacti, and poinsettias are certain to be safe conversation topics. Horticulturists with Iowa State University Extension and Outreach share fun facts. To have more questions answered contact Hortline at 515-294-3108 or hortline@iastate.edu.

What are the differences between Thanksgiving and Christmas cacti?  

Negoi-Cristian/stock.adobe.com/Thanksgiving cactus with pink bloom.Thanksgiving cacti (Schlumbergera truncata) and Christmas cacti (Schlumbergera bridgesii) are similar in appearance. However, the stem segments on the Thanksgiving cactus have two to four pointed teeth, while the stem segments on the Christmas cactus have scalloped edges. The flowering period of Thanksgiving cacti is generally mid-November to late December. Christmas cacti typically bloom from late November to early February.  

Schlumbergera truncata and Schlumbergera bridgesii are epiphytic plants native to the mountainous forests of southeastern Brazil. Plants grow in the crotches of trees and derive water and nutrients from rains and decaying organic matter.  

The stems of Thanksgiving and Christmas cacti are composed of flattened stem segments or phylloclades. The leaf-like phylloclades carry on photosynthesis for the plant.  

Day-length and temperature control the flowering of both Schlumbergera species. Thanksgiving and Christmas cacti are short-day plants. Plants will not bloom properly if exposed to artificial light at night in fall. Flowers may also fail to develop if the plant is exposed to temperatures above 70 degrees Fahrenheit. Night temperatures of 60 to 65 F with slightly warmer daytime temperatures are ideal for flower formation.  

What are some interesting facts about the poinsettia?  

The poinsettia (Euphorbia pulcherrima) is native to southern Mexico and Guatemala. Poinsettias were introduced into the United States by Joel Roberts Poinsett, the United States Minister (ambassador) to Mexico from 1825 to 1829. The specific epithet pulcherrima means pretty or very beautiful. The common name “poinsettia” was chosen by American historian and gardener William H. Prescott in the mid-19th century in honor of the man who introduced the species to the United States.  

The colorful part of the poinsettia, commonly referred to as the plant’s flowers, are actually modified leaves or bracts. The true flowers are yellow to green, button-like objects located in the center of the bracts.  

Poinsettias are short-day plants. Short-day plants grow vegetatively during the long days of summer and produce flowers when days become shorter in fall. In order for poinsettias to flower for Christmas, plants must receive complete, uninterrupted darkness from 5 p.m. to 8 a.m. each day from early October until the bracts show good color, usually around early December. (Most poinsettia cultivars require eight to 10 weeks of short days to flower.)  

Contrary to popular belief, the poinsettia is not poisonous. However, it is not intended for human or animal consumption. Individuals are still advised to keep the poinsettia out of the reach of small children and pets.  

What type of plant is mistletoe?  

Mistletoe is a semi-parasitic plant with small, leathery leaves and small, white berries. Mistletoe plants manufacture their own food, but must obtain water and minerals from the host plant.  

American mistletoe (Phoradendron serotinum) can be found growing in deciduous trees from New Jersey and southern Indiana southward to Florida and Texas. It is the state flower of Oklahoma. Mistletoe sold during the holiday season is gathered in the wild. Most mistletoe is harvested in Oklahoma and Texas.  
The scientific name Phoradendron is derived from Greek and literally means “thief of the tree.”  


Photo of Thanksgiving cactus. Credit: Negoi-Cristian/stock.adobe.com


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